This invention relates to magnifying apparatus and more particularly to a source of illumination for a magnifier.
As one can ascertain, the prior art is replete with numerous patents and other materials which show magnifying lens systems to enable a person to view objects more clearly. As is well known, with the aid of a magnifying glass or a microscope it is possible to bring the object very close to the eye and yet view it as though it were comfortably within the eye's range of accommodation. This is the range of distance within which one can produce a sharply focused image on the retina. As is also well known, the magnifying power of a microscope or a magnifying glass is the ratio of the apparent size of the image of an object formed by the instrument to that of the object seen by the naked eye. Various optical aids have been used to enable close viewing. Many of these optical aids come with a built in light source which enables one to utilize the magnifying glass or the microscope assembly to view various items or objects with the additional light source illuminating the field of view. Such prior art magnifiers present many problems in regard to the nature of the illumination in regard to glare which is caused by the source of illumination and while, in general, are effective to provide magnification, there are various problems associated with the apparatus. As indicated, many of the problems result in glare which emanates from the illumination source as well as uneven illumination of the object to be viewed by the magnifying system. Hence the prior art was cognizant of such problems and offered various solutions. See, for example, U.S. Pat. No. 4,859,032 entitled HAND HELD MAGNIFIER APPARATUS, issued on Aug. 22, 1989 to Richard E. Feinbloom, the inventor herein and assigned to Designs For Vision, Inc., the assignee herein. That patent describes a hand held magnifying apparatus which employs a composite housing. The housing includes a first housing assembly which holds first and second magnifying lenses and which is terminated in a cylindrical hood. A power source is contained in an angled housing which operates to illuminate the object to be viewed by providing a light pattern from the illumination source which light pattern is changed from an elliptical to a circular pattern to thereby uniformly illuminate the text or material to be viewed via the magnifying lens assembly. This is an extremely efficient device but, as indicated above, is a complete and relatively expensive device. As one can ascertain, there are many different types of magnifying assemblies which exist in the prior art. One type of optical magnifier for reading a document comprises a lens enclosed in a metal or plastic sleeve. The user of the magnifier holds the magnifier sleeve and positions the lens over a document to be read. The document is illuminated by ambient light passing through the lens and under the magnifier. This light is reflected back to the user.
In using this particular system, shadows are cast on the document by the magnifier sleeve, by the user's hand and other objects close to the magnifier. Thus the viewing area is not fully or well lighted and the reading process becomes impaired. Such magnifier assemblies as indicated above which essentially comprise a lens enclosed in a metal or plastic sleeve, come in various powers and hence the user can employ different lens assemblies for different reading tasks. While there are devices as shown, for example, in U.S. Pat. No. 4,859,032, which can provide a constant source of illumination, these devices are relatively expensive.
Thus apparatus which will enable one to view a text or other material with uniform illumination in a simple and economical form would be extremely advantageous. The apparatus should have the ability to support a typical magnifying lens which is enclosed in a metal or plastic sleeve while further providing a source of uniform illumination for the supported magnifying lens.